Sheet separating and forwarding machine



' p 21,1954 G. w. TEBBS SHEET SEPARATING AND FORWARDING momma Filed Feb. 16. 1951 I72 ve'rzZ Geo/fie 1 1 Tlbs Patented Sept. 21,1954

SHEET SEPARATING AND FORWARDING MACHINE George William Tebbs, Woodford Green, England, assignor to Headley Townsend Backhouse, Sunningdale, England Application February 16, 1951, Serial No. 211,295

Claims priority, application Great Britain February 17, 1950 3 Claims.

The invention relates to machines for separating individual sheets of paper, card, metal or the like from the top of a pile and for forwardin each sheet from the pile by movement in a direction substantially in the general plane of the sheet and is concerned with such machines of the kind (hereinafter referred to as the kind described) in which the forwarding is effected or controlled by two or more suction grippers operating above the pile to engage each individual sheet and given a movement in the forwarding direction with the sheet and then, after releasing the sheet, a return movement ready to engage the next sheet, the grippers being spaced apart transversely to the direction of forwarding. In machines of the kind described the sheets are usually forwarded on to a conveyor (frequently a tape conveyor) which carries the sheets either individually or as a continuous stream of partly overlapping sheets, to a printing machine or other machine operating on individual sheets. The forwarding suction grippers may also serve to effect the initial separation and elevation of a part of the sheet or the separation and elevation may be effected by other means such as suction grippers which effect an initial elevation of a portion of the sheet and transfer the elevated portion to the forwarding grippers. The complete separation of the sheet is usually effected by an air blast directed between the elevated portion and the remainder of the pile. In machines of the type described the forwarding grippers and/or the separating grippers when provided, may operate above the rear portion of the sheets, considered in the forwarding direction, and necessarily do so when the sheets are to be forwarded as a stream of partly overlapping sheets. Examples of sheet separating and forwarding machines of the kind described above are described in British Specifications Nos. 4 7,041, 489,405 and 475,892.

According to the present invention a sheet separatin and forwarding machine of the kind described is characterised by the feature that the length of the movement of the forwarding grippers while engaging the sheet is adjustable.

A machine having the characteristic feature of the invention has the advantage that the timing of the sheets on the conveyor may be varied. More particularly it is found in practice that as a stiff sheet sags less than a flimsy sheet between the lifting grippers and the front edge of the sheet there tends to be a variation in the timing of the presentation of the front edges of such sheets to a conveyor and hence of the timing of the sheets on the conveyor. The invention provides a simple adjustment whereby this variation in timin between different types of sheets may be corrected.

In one known arrangement of machines of the kind described the forwarding suction grippers are carried by arms dependent from a shaft extending crosswise of the forwarding direction and arranged for oscillation to impart the forwarding and return movements to the forwarding grippers. When the invention is applied to this known arrangement the shaft may be provided with an operating arm and there may be a pushrod pivoted to the operating arm and a cam for imparting reciprocatory movements to the rod to rock the shaft and the radial position of the pivotal connection of the rod to the arm may be adjustable to vary the effective length of the arm and consequently the length of the strokes of the grippers.

Two specific examples of machines according to the invention will now be described with reference to the accompanying drawings in which:

Figure 1 is a perspective view of the forwarding mechanism of a sheet separating and forwarding machine, and

Figure 2 is an enlarged view of an alternative arrangement to that employed in the machine shown in Figure 1 for eflecting adjustment of the lengths of the movements of the forwarding grippers.

The machine shown in Figure 1 operates to separate, by well-known means not shown, individual sheets I from the top of a pile 2. The separated sheets are taken, in turn, by suction grippers 3 which move forward with the sheet to engage the front edge of the sheet with a tape conveyor 4 by which the sheets are carried as a continuous stream to front registering devices 5. An air blast is directed under the separated sheet to assist in the forwarding which is controlled by the grippers.

The grippers are carried by tubes 6- dependent from a cross-shaft 1 supported in bearings in fixed frame members 8. At one end of the shaft there is an arm 9 connected to aDush-rod I 0 which is arranged for reciprocation by a cam II on an operating shaft l2, the shaft bein embraced by a guide fork on the end of the pushrod. There is a pivotal connection between the rod l0 and the arm 9 comprising a first order lever It on the arm having one end pivoted at I5 to the push-rod and the other end connected to an adjusting screw l6 carried by the shaft 1. The arrangement is such that rotation of the screw I8 rocks the lever about its connection to the arm and varies the radial distance of the pivotal connection from the shaft I, consequently the angular movement of the shaft 1 and the length of the strokes of the grippers 3 are varied.

In the arrangement shown in Figure 2, the pivotal connection between the push rod l0 and the operating arm 9a comprises a block pivotally attached to the push-rod and slidable in a radially extending slot 21 in the arm and there. is a guide 22, extending transverse to the direction of movement of the rod, for the, block, the position of the guide radially of the. arm being adjustable. The guide is pivotally secured at one end 23 to the frame 24 of the machine and the other end is adjustably supported from the frame by screw means 25 for varying the radial distance. The guide is inthe form of a slotted lever and the block is provided with a roller 26 running in the slot.

It is an advantage of the above example of the invention that the stroke of the forwarding grippers may be varied during the running of the machine and the arrangement described in the sec- 0nd of the above examples is particularly conveni'ent in this respect because the adjusting screw does not move during the operation of the machine as does the screw in the first example.

I claim: r

l. A machine for separating individual sheets or" papers, card or the like from the top of a pile and for forwarding each sheet from the pile by movement in a direction substantially in the general plane of the sheet, which machine is of the kind having an oscillatable shaft extending crosswise of the forwarding direction above the pile, at least two arms dependent from the shaft at spaced positions along the length thereof, a corresponding number of suction grippers secured one at the lower end of each arm, and means for oscillating the shaft comprising an operating arm secured to the shaft, a push-rod pivoted to the operating arm and a cam for imparting reciprocatory movements to the rod to oscillate the shaft and thereby to impart forwarding and return movements to the grippers, and which machine is characterised by means for varying the radial position of the pivotal connection of the rod to the operating arm to vary the effective length of the operating arm and consequently to vary the length of the movements of the grippers.

2. A machine as claimed in claim 1 in Which the means for varying the effective length of the operating arm comprise a lever pivoted on the arm intermediate in the length of the lever and having at one end the pivotal connection aforesaid to the push rod, and at the other end an adjusting screw carried by the oscillatable shaft aforesaid, the screw being arranged for operation to rock the lever on the operating arm.

3. A machine as, claimed in claim 1 in which the pivotal connection between the push rod and the operating arm permits relative sliding movement of the rod and arm lengthwise of the arm to vary the effective length thereof and in which there is a frame member, a lever extending transversely to the length of the operating arm and pivoted to the frame member, screw means extending between the frame member and the lever and operable to rock the lever about its pivot and a pivotal sliding connection between the lever and the push rod.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,475,621 Christophel Nov. 27, 1923 1,814,021 Buttner July 14, 1931 2,039,699 Biazzi May 5, 1936 2,980,010 Rowlands et al. May 11, 1937 2,341,521 Baker et a1 Feb. 15, 1944 OTHER REFERENCES Kents Mechanical Engineers Handbook, the volume (not numbered) entitled Design Shop Practicel1.th Edition, Section 8,v page 3 (humbered as 8-03.).. Published by John Wiley and Sons in. 1938 (Copy available in Division 17.) 

